3D retopology & clean geometry – BMW i Vision Dee

Naturally, the car designers use 3D software for their work, and it stands to reason that this data should be interchangeable—which is true. The problem is that they usually don’t build their models out of vertices and polygons, but with CAD software, i.e., using mathematical curves to describe geometric forms. You can export and transform this CAD data into the polygonal data needed for rendering, and if you don’t require deformable geometry, it usually isn’t a major issue.

However, as you can see in the examples below, the exported underlying mesh topology is too inconsistent and chaotic to properly rig and animate a character without risking artifacts and errors. This is where 3d retopology comes into play: the object is rebuilt with a clean, evenly distributed mesh while maintaining 100% fidelity to the original geometry.

Luckily, Autodesk Maya offers a dedicated set of tools specifically developed for 3d retopology. You can keep the original CAD data as a snapable surface in the viewport and draw new quads and entire rows of polygons directly on top of it. These tools greatly reduce the workload and make the process far less daunting.

With this now easily subdividable 3D model of the car, the fantastic team at Aixsponza was able to produce a polished character animation, fully leveraging the clean, animation-ready geometry achieved through careful 3d retopology.